JP2005244997A - Method and system for choosing radio channel by mobile device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method to choose radio channel using two or more interfaces at parallel level 2 to facilitate handoff at level 3, and to provide mobile device. <P>SOLUTION: The method and device maintains service of the first transceiver in active state in the first connection at upper level 3, establishes the second connection of the second transceiver at the upper level 3, and switches service to the second connection. To establish a proper connection at the level 3, the mobile device can evaluate a candidate channel in the standard related to the service in connecting status in order to secure retention of service quality on a new connection. The mobile device can also adapt the service in active state to the candidate channel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

(Field of Invention)
The present invention relates to wireless mobile devices, and more particularly, to a method and system for selecting a wireless channel by a mobile device.

(Background of the present invention)
Many of the mobile devices available today offer much more complex functions than simple voice communications. For example, many mobile devices allow users to access a remote server or remote site on a public network such as the Internet. Among these mobile devices are devices that allow users to make Voice-over-IP (VoIP) calls. Other mobile devices allow users to receive streaming data from remote resources such as streaming video or audio data.

  This higher level of functionality, particularly the ability to receive real-time streaming data, provides a particular quality of service. For example, a mobile device must ensure that streaming data such as a VoIP phone is retained while roaming. Thus, when roaming from one base station or cell in the network to another base station or cell, the network is sufficient to handle call handoffs between base stations without introducing significant delays in streaming data. In order to ensure that there is a certain amount of time, a certain amount of latency must be provided in the communication.

  A particular difficulty arises when a mobile device roams from one network to another of a different type. For example, a mobile device can initiate and establish a call within a General Packet Radio System (GPRS) network, and then geographically into a region provided from a wireless local area network (WLAN) or IEEE 802.11 coverage. Can move. With existing mobile devices, when a mobile device switches a call to a new network, it may not be possible to retain the services that take place on the call.

  To facilitate a level 3 handoff, a mobile device and method for performing radio channel selection utilizing one or more simultaneous level 2 interfaces.

(Outline of the present invention)
The method and device of the present invention maintain active service on a first level 3 connection via a first transceiver and establish a second level 3 connection via a second transceiver; Switch service to second level 3 connection. In order to establish an appropriate level 3 connection, the mobile device can verify the candidate channel against the criteria associated with the active service to ensure that the quality of service can be maintained on the new connection. Can be evaluated. In certain embodiments, active services may be adapted to operate on candidate channels that have different characteristics than existing channels.

In one aspect, the present invention provides a method for wireless channel selection by a mobile device, the mobile device communicating with a wireless network. A method creates a first connection of a wireless network on a first channel, establishes service between a mobile device and a remote point on the first connection, and on a second channel Creating the second connection of the wireless network, switching the service to the second connection, and terminating the first connection, wherein the step of creating the second connection comprises the steps of: Selecting a channel and evaluating the characteristics of the second channel against a service criterion associated with a service established on the first connection.

  In another aspect, the present invention provides a mobile device for wireless channel selection, which communicates with a wireless network. The mobile device has a first transceiver that creates a first connection with a wireless network on a first channel, and a second transceiver that creates a second connection with the wireless network on a second channel; A switching module coupled to the first transceiver and the second transceiver, the switching module instructing the first transceiver to create a first connection, the remote on the mobile device and the first connection A switching module that establishes service between the points, selects a second channel, and instructs the second transceiver to create a second connection. In addition, the device includes a memory that includes a list of candidate channels and their characteristics and includes service criteria associated with the service. The switching module switches service from the first connection to the second connection, the switching module reads a list of candidate channels and compares its characteristics against the service criteria for at least one of the candidate channels.

  In a further aspect, the present invention provides a computer readable medium comprising code means for a device of the present invention that implements a method according to the present invention.

Accordingly, in one aspect, the present invention provides
A method of wireless channel selection by a mobile device (10), wherein the mobile device (10) communicates with a wireless network (50) and a first of the wireless network (50) on a first channel (90). Creating a connection; establishing a service between the mobile device (10) and a remote point on the first connection; and a second of a wireless network (50) on a second channel (92). Creating a second connection, switching the service to the second connection, and terminating the first connection;
The step of creating the second connection includes selecting the second channel (92) and the second criteria relative to a service criterion associated with the service established on the first connection. Evaluating a characteristic of the channel (92).

  In one embodiment, the characteristic includes bandwidth, and the service criteria includes a minimum bandwidth requirement.

  In a preferred embodiment, the characteristic includes latency and the service criteria includes a latency request.

  In a preferred embodiment, the characteristic includes an average bandwidth and the service criteria includes an average bandwidth request.

  In a preferred embodiment, the characteristic includes a security setting, and the service criteria includes a security setting request.

  In a preferred embodiment, the characteristic of the second channel (92) does not meet the service criteria, and the method comprises the step of adapting the service to the characteristic of the second channel (92). Include.

  In a further preferred embodiment, the service includes audio and video, and the adapting step includes dropping the video to transmit only the audio.

  In a further preferred embodiment, the service includes transmission of an encoded medium, and the adapting step includes modifying a codec used to encode and decode the encoded medium.

  In a further preferred embodiment, creating the second connection includes selecting the second channel (92) and requesting resources from the wireless network (50).

  In a further preferred embodiment, the wireless network (50) includes an anchor point (98), the first connection includes a first path (94) to the anchor point (98), and the second The step of creating a connection comprises establishing a second path (96) to the anchor point (98).

In another aspect, the present invention is a mobile device (10) for radio channel selection, wherein the mobile device (10) communicates with a wireless network (50), wherein the mobile device (10)
A first transceiver (14) for creating a first connection with a wireless network (50) on a first channel;
A second transceiver (16) for creating a second connection with the wireless network (50) on the second channel;
A switching module (70) coupled to the first transceiver (14) and the second transceiver (16), the switching module (70) being connected to the first transceiver (14) by the first transceiver (14); To establish a service between the mobile device (10) and a remote point on the first connection, select the second channel, and select the second transceiver (16 Switching module (70) instructing to create the second connection;
A memory including a list of candidate channels and their characteristics (72) and including a service criteria (74) associated with the service;
The switching module (70) switches the service from the first connection to the second connection;
The switching module (70) reads the list (72) of candidate channels and compares the characteristics to at least one of the candidate channels against the service criteria (74). A mobile device (10) is provided, characterized in that a channel is selected.

  In one embodiment, the switching module (70) instructs the first transceiver (14) to terminate the first connection when the service is switched to the second connection. Features.

  In another embodiment, the characteristic includes bandwidth, and the service criteria (74) includes a minimum bandwidth requirement.

  In another embodiment, the characteristic includes time spent and the service criteria (74) includes a latency request.

  In another embodiment, the characteristic includes an average bandwidth and the service criteria (74) includes an average bandwidth request.

  In another embodiment, the characteristic includes a security setting, and the service criteria (74) includes a security setting request.

  In another embodiment, the characteristic of the second channel does not meet the service criteria (74) and the switching module (70) adapts the service to the characteristic of the second channel.

  In a preferred embodiment, the service includes audio and video, and the switching module (70) adapts the service by dropping the video to transmit only the audio.

  In a preferred embodiment, the service includes transmission of an encoded medium and the switching module (70) adapts the service by modifying a codec used to encode and decode the encoded medium. .

  In a preferred embodiment, the switching module (70) outputs a request for resources to the second transceiver (16) for transmission to the wireless network (50) to establish the second connection. It is characterized by.

  In a preferred embodiment, the wireless network (50) includes an anchor point (98), the first connection includes a first path (94) to the anchor point, and the second connection includes: It includes a second path (96) to the anchor point (98).

  In another aspect, the present invention provides a computer readable medium comprising code means executable on the processor (38) of the device implementing the method.

  Still other aspects and features of the present invention will become apparent to those skilled in the art upon review of the following detailed description in conjunction with the drawings.

  The method and device of the present invention maintain active service on a first level 3 connection via a first transceiver and establish a second level 3 connection via a second transceiver; Switch service to second level 3 connection. In order to establish an appropriate level 3 connection, the mobile device can verify the candidate channel against the criteria associated with the active service to ensure that the quality of service can be maintained on the new connection. Can be evaluated. In certain embodiments, active services may be adapted to operate on candidate channels that have different characteristics than existing channels.

(Description of specific embodiments)
The following description of one or more specific embodiments of the present invention is not intended to limit the invention to a particular computer programming language or system architecture implementation. The present invention is not limited to a particular operating system, mobile device architecture, or computer programming language.

  The following description refers to selecting a channel and operating a channel service. It is understood that the term channel and the concept of selecting a channel is meant to encompass selecting a channel from among different frequencies and / or different channels.

  First, refer to FIG. 1 showing a mobile device 10 and a wireless communication network 50. The wireless communication network 50 includes a first base station 80 and a second base station 82 coupled to a core network 84. The core network 84 may include a collection of different types of networks interconnected. For example, the core network 84 may include a GPRS network coupled to a WLAN and the Internet. Those skilled in the art will appreciate that the core network 84 may encompass a variety of other interconnected networks.

  The mobile device 10 includes a first transceiver (first transmitter) 14 and a second transceiver (second transmitter) 16. The mobile device 10 can establish communication with the wireless communication network 50. For example, the first transceiver 14 may have a first link 90 with a first base station 80 and the second transceiver 16 may have a second link 92 with a second base station 82. .

  In normal operation, the mobile device 10 uses one of the transceiver 14 and the transceiver 16 to establish and maintain a link with the base station 80 or the base station 82. Using this link, for example, a communication service such as a voice telephone is held. Accordingly, the mobile device 10 establishes a level 2 (L2) connection to the wireless communication network 50 over link 90 or link 92 and then a level 3 (L3) connection with the management domain to create a communication service. Establish. For example, the first transceiver 14 may have an active service on the first link 90 to the first base station 80, such as a VoIP session. This service operates on the L3 connection between the mobile device 10 in the wireless communication network 50 and the remote point using the first link 90.

  The mobile device 10 can determine that it has moved to an area that is better served by another base station. In this case, it tries to find an alternative link for the other base station. Mobile device 10 may make this determination as a result of monitoring signal strength according to appropriate criteria, as will be appreciated by those skilled in the art. The mobile device 10 may scan the broadcast information received from the first base station 80 or find an available channel on the second base station 82 via the broadcast information. When the mobile device 10 finds an alternative channel, the mobile device 10 tunes to a new channel and obtains broadcast information from the second base station 82. There can be multiple candidate channels.

  Based on the broadcast information about the new channel, the mobile device 10 determines whether the channel is available. The mobile device 10 also evaluates the characteristics of the channel in light of the type of service currently running on the mobile device. Depending on the type of service, a minimum channel feature is required from any candidate channel to hold the service. For example, the type of service may be a high bandwidth service. In this case, low bandwidth channels are inappropriate. Other factors, including cost and reach, can also be factors to determine. Reachability refers to the ability to reach the same entity within the wireless communication network 50 that is providing active services.

  When a new channel is approved from the mobile device 10, the mobile device 10 requests resources from the wireless communication network 50. That is, the mobile device 10 requests connectivity between L2 and L3. If the second link 92 is established and the resource is granted, the mobile device 10 evaluates whether the granted resource is sufficient to operate the service. If the resources are sufficient, existing services operating on the first link 90 are switched to the second link 92.

  In other embodiments, the second link 92 has characteristics that are different from the first link 90, such as lower bandwidth or longer average latency. The mobile device 10 can adapt its service to operate on the second link 92. In other words, the service is modified based on the characteristics of the new channel. This adaptation may include changing the codec used for that service. For example, a service that includes audio and / or video may consume less bandwidth by modifying the codec used for audio and / or video, or by dropping the video and transmitting only the audio. Can be modified. It is understood that other modifications can be made to the service to ensure that the service works well on new channels with different characteristics.

  Reference is made to FIG. 2, which shows a block diagram of FIG. 1 in a roaming situation. The core network 84 includes an anchor point 98. Anchor point 98 may be a router, server, or other node in wireless communication network 50.

  Anchor point 98 is coupled to one or more servers 100, 102, 104 that support communication services. In other embodiments, anchor point 98 is one of servers 100, 102, 104 that provide communication services. The communication service is represented by a first data stream 94 to an anchor point 98 on the first link 90. Anchor point 98 processes first data stream 94 and transmits data stream 94 to one or more servers 100, 102, 104.

  When the mobile device 10 requests network resources to establish the second link 92, it asks to establish a connection to the anchor point 98. To create a second link 92 and establish an L3 connection to support the transfer of communication services, the mobile device 10 performs packet communication from the anchor point 98 to the mobile device 10 on the second link 92. It may be required to assign an IP address for ease. The request for network resources may also include an authentication step, an authorization step, and steps to ensure that there is sufficient bandwidth and that the latency level is acceptable.

  If these resources are granted and the mobile device 10 determines that this resource is sufficient to support an existing communication service, a second data stream 96 is established to support the communication service.

  Thus, by establishing overlapping L2 connectivity, the mobile device 10 can select and acquire resources on the new channel and move services to the new channel without losing L3 connectivity. This minimizes the waiting time in handoff.

  Reference is made to FIG. 3 showing a block diagram of a mobile device 10 in an example embodiment. In this embodiment, the mobile device 10 has data and, if necessary, voice communication capability. In the example embodiment, mobile device 10 has the ability to communicate with other computer systems on the Internet. Depending on the functionality provided by the mobile device, in various embodiments, the mobile device, among other devices, may be a data communication device, a multiple mode communication device configured for both data communication and voice communication, mobile It can be a telephone, a personal digital assistant (PDA) available for wireless communication, or a computer system with a wireless modem.

  In this embodiment, the mobile device 10 includes a communication subsystem 12 that includes a first transceiver 14, a second transceiver 16, and components associated therewith (eg, processor 20). The processor 20 includes a digital signal processor (DSP) in one embodiment. In certain embodiments, the communication subsystem includes a local oscillator (LO) (not shown), and in certain embodiments, the communication subsystem 12 and the microprocessor 38 share an oscillator. As will be apparent to those skilled in the art, the specific design of the communication subsystem 12 depends on the communication network in which the mobile device is intended to operate. Transceiver 14 and transceiver 16 may have multiple separate antennas or may share a single antenna.

  The signal received from the antenna via the wireless communication network 50 is an input to one of the transceiver 14 or transceiver 16, which is commonly used for signal amplification, frequency down conversion, filtering, etc. Can perform the functions of a simple transceiver. In a similar manner, the signal to be transmitted is processed by the processor 20 including, for example, modulation and encoding. A signal to be transmitted is also input to one of the transceivers 14 or 16 for frequency upconversion, filtering, amplification, and transmission over the wireless communication network 50.

  Mobile device 10 includes a microprocessor 38 that controls the overall operation of the mobile device. Microprocessor 38 interacts with communications subsystem 12 and also includes display 22, flash memory 24, random access memory (RAM) 26, auxiliary input / output (I / O) subsystem 28, serial port 30, keyboard or It also interacts with the keypad 32, speaker 34, microphone 36, short range communication subsystem 40, and other device subsystems generally designated as 42.

  Some of the subsystems shown in FIG. 1 perform communication-related functions. On the other hand, other subsystems may provide “resident” or functionality on the device. In particular, subsystems such as keyboard 32 and display 22 are used for both communication-related functions such as entering text messages for transmission over a communication network and device resident functions such as a calculator or task list. Can be done.

  The operating system software 54 and various software applications 58 used by the microprocessor 38 are stored in a persistent storage device (persistent store), such as the flash memory 24 and similar storage elements, in one example embodiment. Those skilled in the art will appreciate that operating system 54, software application 58, or portions thereof, can be temporarily loaded into a volatile storage device such as RAM 26. Consider that received communication signals may also be stored in RAM 26.

  The microprocessor 38 is preferably capable of executing software applications 58 on the mobile device in addition to operating system functions. For example, a set of predetermined software applications 58 that control basic device operations, including at least data and voice communication applications, are typically installed on the mobile device 10 during the manufacturing process. In addition, the software application 58 is loaded into the mobile device 10 above the wireless communication network 50, auxiliary I / O subsystem 28, serial port 30, short range communication subsystem 40, or other suitable device subsystem 42. Can also be installed by the user in the RAM 26 or non-volatile storage device for execution by the microprocessor 38. Such flexibility in application installation increases the capabilities of mobile devices and may provide improved device functionality, improved communication-related functionality, or both. For example, a secure communication application may allow electronic commerce functions and other financial transactions to be performed using the mobile device 10.

  In the data communication mode, received signals such as text messages and web page downloads are processed by the communication subsystem 12 and input to the microprocessor 38. This is preferably further processed to output the received signal to the display 22 or alternatively to the auxiliary I / O device 28. The user of the mobile device 10 may also use the keyboard 32 with the display 22 and optionally the auxiliary I / O device 28 to configure data items in the software application 58, such as e-mail messages. Such configured items may be transmitted over the communication network via the communication subsystem 12.

  The serial port 30 in FIG. 1 may typically be desired to be synchronized with a user's desktop computer (not shown), but can be implemented in any component device, a personal digital assistant (PDA) type communication device. . Such a serial port 30 allows a user to set priorities through an external device or software application, and in addition to the method via the wireless communication network 50, the serial port 30 allows information and software downloads to be transmitted to the mobile device 10. To expand the capabilities of mobile devices.

  Further, the short range communication subsystem 40 is a component that can provide communication between the mobile device 10 and different systems or devices that need not be similar devices. For example, subsystem 40 may comprise an infrared device, associated line, component, or Bluetooth ™ communication module to provide communication between the similarly executable system and device. The mobile device 10 can be a portable device.

  The wireless communication network 50 may be a wireless packet data network (eg, Mobitex ™ or DataTAC ™) that provides wireless coverage for the mobile device 10 in one example embodiment. In addition, the wireless communication network 50 includes GSM (Global System for Mobile Communication), GPRS, Code Division Multiple Access (CDMA), or EDGE (Enhanced DataUssT for USM). It can be a voice and data network such as various three generation networks.

  Reference is made to FIG. 4 showing a block diagram of an embodiment of the communication subsystem 12. In addition to the first transceiver 14 and the second transceiver 16, the communication subsystem 12 includes a switching manager 70, a radio network database (RND) 72, and a user data database (UDD) 74. The first transceiver 14 and the second transceiver 16 each include a transmission module 60, 63, a reception module 62, 65, and a radio resource sublayer manager (RRM) 61, 64.

  Like reference numerals used in different figures refer to like components.

  The switching manager 70 manages connections between the mobile device 10 (FIG. 1) and the wireless communication network 50 (FIG. 1). The switching manager 70 requires that a dedicated source establish the data transfer received by one or both transceivers 14, 16 and coordinate the information. The switching manager 70 alerts one of the trussie bar 14 or truss bar 16 when a new channel search is required. The switching manager 70 also indicates whether the source data 76 proceeds to the first trussieber 14 or the second trussieber 16 for transmission. The switching manager 70 may also perform mobility management functions such as authentication.

  The wireless network database 72 stores information about candidate channels from which locations have been found and broadcast information from which locations have been found. The radio network database 72 may also store signal strength information. Thus, the wireless network database 72 keeps up-to-date records of potential channels and their characteristics.

  User database 74 stores information regarding attributes to be used in selecting a channel. These attributes may include signal strength, minimum bandwidth, average bandwidth, minimum latency, average latency, maximum latency, security settings, technology type, and other attributes.

  The sub-layer manager (RRM) 61, 64 of each radio source is responsible for radio link control and intermediate access control (RLC / MAC). The RRMs 61 and 64 give instructions to the receiver modules 63 and 65 so as to scan an appropriate frequency band. If a matching channel is found, RRMs 61 and 64 indicate the position of the broadcast information. When the broadcast information informs the surrounding channels, the RRM 61, 64 instructs the receiver modules 63, 65 to tune to those channels and to acquire the signal strength and broadcast information. The RRM gives the switching manager 70 information gathered from the found channels. The switching manager 70 then stores the information in the wireless network database 72. The RRMs 61 and 64 dynamically update the information in the radio network database 72 as the signal strength of the found channel changes.

  It will be understood that various parts of the communication subsystem 12 of the block diagram of FIG. 4 may be implemented by other parts or subsystems of the block diagram of FIG. For example, UDD 74 or RND 72 may be stored in flash memory 24 (FIG. 3) or in RAM 26 (FIG. 3). The switching manager 70 may be implemented through the microprocessor 38 or through a dedicated target element such as the processor 20.

  The switching manager 70 selects the channel used for communication and sends control information to one of the transceiver 14 and the transceiver 16 to instruct it to tune to the selected channel. The switching manager 70 also sends a request for resources (via one of the transceiver 14 and the transceiver 16). Once the resource is granted, the switching manager 70 commands the source data 76 to proceed to the tuned trussie 14 or 16.

  Reference is now made to FIG. 5 in conjunction with FIG. FIG. 5 shows, in flowchart form, a method 200 for radio channel selection according to the present invention. Method 200 begins at step 202. Here, the switching manager 70 selects one of the available channels and instructs the first transceiver 14 to tune to the selected channel. The switching manager 70 then sends a request for resources to the wireless communication network 50 using the first transceiver 14 at step 204. When the wireless communication network 50 recognizes the resource, then, at step 206, the source data 76 is directed to the first transceiver 14 for transmission.

  A communication service, such as a VolP call, is established using the link setup on the channel selected using the first transceiver, while the second transceiver 16 sets the environment for the alternative channel at step 208. to scan. The second transceiver 16 can scan any channel originally found by the first transceiver, or the second transceiver 16 can find additional channels or new channels. The second transceiver 16 provides the updated channel information in the wireless network database 72 to the switching manager 70. When the second transceiver 16 indicates that the previously discovered channel is unavailable due to loss of signal strength or loss of availability, the second transceiver 16 notifies the switching manager 70 and the wireless network. Information in the database is updated accordingly. Those channels that have become unavailable are marked as such and are then dropped together from the radio network database 72 when the channels are not found again within the appropriate time.

  The second transceiver 16 scans for available channels and when the radio network database 72 is updated, the first transceiver 14 performs signal strength monitoring on the selected channel on which the service is operating. Do. When the first transceiver 14 detects in step 210 that the signal strength has dropped below a threshold defined by the appropriate standard, the method 200 proceeds to step 212 and selects a new channel. .

  In steps 212, 213, 214, the switching manager 70 selects a new candidate channel and instructs the second transceiver 16 to tune to the new channel. When the second transceiver 16 finds a new channel, the second transceiver 16 informs the switching manager 70, which sends a request for resources from the wireless communication network 50 (FIG. 1). Acquiring resources includes acquiring the required bearer channel, which includes establishing a level 3 network connection with anchor point 98 (FIG. 2). The anchor point 98 is a point in the core network 84 (FIG. 2), and has already processed the first data stream 94 (FIG. 2) for a service operating on the first link 90 (FIG. 2). Is going. Anchor point 98 may be a server providing service or may be an intermediate point in core network 84. Establishing a level 3 network connection with anchor point 98 may include assigning a new IP address to the mobile device that may be different from the IP address used for first link 90. Thus, when resources are granted, the mobile device 10 has two current level 3 communication paths established in the wireless communication network 50.

  When the resource is granted, the switching manager 70 causes the source data 76 to be routed to the second transceiver 16 for transmission.

  If the resource is not recognized, the switching manager 70 selects a new candidate channel and repeats the attempt to acquire the resource.

  The steps of selecting a new channel and switching the service to the new channel shown in steps 212, 213, 214 are shown in more detail in FIG. FIG. 6 illustrates, in flowchart form, a method 300 for selecting a new candidate channel and a method 300 for switching services to a new channel.

  The method 300 begins when the switching manager 70 (FIG. 4) decides to select a new channel, such as in response to a decrease in the signal strength of the currently used channel. In step 302, the switching manager 70 reads the selection criteria from the user database 74 (FIG. 4). The selection criteria reflects the characteristics of the channel necessary to maintain a certain quality of service based on the type of service. The selection criteria are the type of service running on the mobile device 10 (eg, VoIP, streaming video, simple e-mail, etc.) and the bandwidth requirements (eg, some quality of service standard) associated with the type of service. (Minimum bandwidth requirement to maintain (QoS)) and any other channel characteristics associated with the type of service. Other channel characteristics may include latency associated with link, security, available settings and technology types (eg, WLAN, GPRS, EDGE, W-CDMA, etc.).

  In step 340, the switching manager 70 determines which candidate channels are available by referring to the wireless network database 72 (FIG. 4). From the candidate channels, the switching manager 70 selects a first candidate at step 306. The selection may be based on a comparison of channel characteristics and channel requirements stored in the wireless network database 72 provided by the user database 74. Alternatively, candidate channels stored in the radio network database 72 are pre-filtered by the switching manager 70 for channel requests during periodic updates of the radio network database 72. In such an embodiment, the radio network database 72 may include only candidate channels that appear to meet the channel requirements. Accordingly, the switching manager 70 may select any one of the candidate channels. A suitable algorithm can even be used to select from multiple candidate channels. The algorithm may include bandwidth, signal strength, and other characteristic information for candidate channels.

  After selecting the candidate channel, at step 308, the switching manager 70 instructs the second transceiver to find the candidate channel and sends a request request to the wireless network 50. When the resource is rejected, the switching manager 70 tries the next candidate channel. When the resource is granted, at step 310, switching manager 70 may accept or reject the candidate channel by comparing the granted resource to the channel request obtained at step 302. When a channel is rejected, the switching manager 70 tries the next candidate channel.

  When the granted resource is appropriate, at step 312, the service is switched to the newly established connection on the new channel. When the service is switched to a new channel using the second transceiver 16 (FIG. 1), the connection using the first transceiver 14 (FIG. 1) is dropped and the first transceiver 14 scans for a new candidate channel. The wireless network database 72 is updated. The overlapping level 3 connectivity resulting from method 300 provides a low latency handoff for services.

  In step 314, if the candidate channel is exhausted without finding an available channel, the handoff is unsuccessful and the service remains on the original channel.

  In other embodiments, when a candidate channel and resource, or candidate channel or resource, is found to be insufficient to meet service criteria, the switching manager 70 may function on the channel where the service is available. May be ordered to be changed or adapted. For example, a service that includes streaming video data may need to be changed to streaming audio alone or to a lower resolution or refresh rate streaming video in order to function properly over a narrower bandwidth connection.

  The method and device of the present invention maintains a service in service on a first connection on a first transceiver, on a level 3 first connection, and establishes a second connection on a level 3 on a second transceiver. Once established, then switch service to the second connection. In order to establish a level 3 proper connection, the mobile device evaluates candidate channels against criteria associated with the connected service to ensure that the quality of service is preserved on the new connection. And the active service can be adapted to the candidate channel.

  The present invention may be implemented in other specific forms without departing from the spirit and essential characteristics of the invention. Adaptations and variations of the present invention will be apparent to those skilled in the art. Accordingly, the above-described embodiments are considered to be illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalents of the claims are therefore intended to be embraced within the invention.

FIG. 2 is a block diagram of an embodiment of a mobile device and a wireless communication network. FIG. 2 is a block diagram of FIG. 1 in a moving situation. FIG. 6 is a block diagram for an embodiment of a mobile device. FIG. 4 is a block diagram of an embodiment of a communication subsystem for the mobile device of FIG. 5 is a flowchart of a method for selecting a radio channel by a mobile device. FIG. 6 is a flowchart of a method for selecting a new candidate channel and switching a service to a new channel.

Explanation of symbols

10 mobile device 12 communication subsystem 14 first transceiver 16 second transceiver 20 processor 22 display 24 flash memory 26 random access memory (RAM)
28 Auxiliary I / O Device 30 Serial Port 32 Keyboard 34 Speaker 36 Microphone 38 Microprocessor 40 Short Range Communication 42 Other Device Subsystem 50 Wireless Network 54 Operating System 58 Software Application 60, 63 Transmit Module 61, 64 Radio Resource Sublayer Manager (RRM)
62, 65 Reception module 70 Switching manager 72 Wireless network database 74 User data database 76 Source data

Claims (22)

A method of wireless channel selection by a mobile device (10), wherein the mobile device (10) communicates with a wireless network (50) and a first of the wireless network (50) on a first channel (90). Creating a connection; establishing a service between the mobile device (10) and a remote point on the first connection; and a second of a wireless network (50) on a second channel (92). Creating a second connection, switching the service to the second connection, and terminating the first connection;
The step of creating the second connection includes selecting the second channel (92) and the second criteria relative to a service criterion associated with the service established on the first connection. Evaluating the characteristics of the channel (92).   The method of claim 1, wherein the characteristic includes bandwidth and the service criteria includes a minimum bandwidth requirement.   3. A method according to claim 1 or claim 2, wherein the characteristic comprises a latency and the service criteria comprises a latency request.   The method according to claim 1, wherein the characteristic includes an average bandwidth, and the service criterion includes an average bandwidth request.   The method according to claim 1, wherein the characteristic includes a security setting, and the service criterion includes a security setting request.   The characteristic of the second channel (92) does not meet the service criteria, and the method includes adapting the service to the characteristic of the second channel (92). The method according to any one of 1 to 5.   The method of claim 6, wherein the service includes audio and video, and the adapting step includes dropping the video to transmit only the audio.   The method of claim 6, wherein the service includes transmission of an encoded medium, and wherein the adapting step includes modifying a codec used to encode and decode the encoded medium. 9. Creating the second connection comprises selecting the second channel (92) and requesting resources from the wireless network (50). The method described in 1.   The wireless network (50) includes an anchor point (98), and the first connection includes a first path (94) to the anchor point (98) to create the second connection The method according to any of the preceding claims, characterized in that the step comprises establishing a second path (96) to the anchor point (98). A mobile device (10) for radio channel selection, the mobile device (10) communicating with a wireless network (50), wherein the mobile device (10)
A first transceiver (14) for creating a first connection with a wireless network (50) on a first channel;
A second transceiver (16) for creating a second connection with the wireless network (50) on the second channel;
A switching module (70) coupled to the first transceiver (14) and the second transceiver (16), the switching module (70) being connected to the first transceiver (14) by the first transceiver (14); To establish a service between the mobile device (10) and a remote point on the first connection, select the second channel, and select the second transceiver (16 Switching module (70) instructing to create the second connection;
A memory including a list of candidate channels and their characteristics (72) and including a service criteria (74) associated with the service;
The switching module (70) switches the service from the first connection to the second connection;
The switching module (70) reads the list (72) of candidate channels and compares the second channel by comparing its characteristics against the service criteria (74) for at least one of the candidate channels. Mobile device (10), characterized in that a channel is selected.   The switching module (70), characterized in that when the service is switched to the second connection, the first transceiver (14) is instructed to terminate the first connection. 11. The mobile device according to 11.   13. A mobile device according to claim 11 or claim 12, wherein the characteristic comprises bandwidth and the service criteria (74) comprises a minimum bandwidth requirement.   14. A mobile device according to any of claims 11 to 13, wherein the characteristic includes time on hand and the service criteria (74) includes a latency request.   15. A mobile device according to any of claims 11 to 14, wherein the characteristic comprises an average bandwidth and the service criteria (74) comprises an average bandwidth request.   The mobile device according to any of claims 11 to 15, wherein the characteristic includes a security setting and the service criteria (74) includes a security setting request.   17. The characteristic of the second channel does not meet the service criteria (74) and the switching module (70) adapts the service to the characteristic of the second channel. A mobile device according to the above.   The mobile device according to claim 17, wherein the service comprises audio and video, and the switching module (70) adapts the service by dropping the video to transmit only the audio.   18. The service of claim 17, wherein the service includes transmission of an encoded medium, and the switching module (70) adapts the service by modifying a codec used to encode and decode the encoded medium. The listed mobile device.   The switching module (70) outputs a request for resources to the second transceiver (16) for transmission to the wireless network (50) to establish the second connection, The mobile device according to claim 11.   The wireless network (50) includes an anchor point (98), the first connection includes a first path (94) to the anchor point, and the second connection includes the anchor point (98). 21. Mobile device according to any of claims 11 to 20, comprising a second path (96) to).   Computer-readable medium comprising code means executable in a processor (38) of a device according to any of claims 11 to 21 for implementing the method according to any of claims 1 to 10.

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